The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In general, a global navigation satellite system (GNSS) is a system that measures a location of a user using triangulation on the basis of signals received from satellites revolving around the earth. Thus, quality of signals from the satellites greatly affects accuracy of the location of the user, and a high level of location accuracy is provided in an open sky in which signals are easily obtained.
However, positioning performance may be problematic in an environment, like the downtown area or tunnels, in which satellite signals are limited or interrupted. In particular, in the downtown area in a compact mass of high-rise buildings, satellite signals are frequently interrupted, interfered and/or distorted by the high-rise buildings, causing a significant positioning error, which results in a reduction in accuracy of positioning of the GNSS.